The science
The two carriages are tied by one rope over a drum, so they form one degree of freedom with combined mass M = m1 + m2. Net force along the slope: F = F_drive + (m2 - m1) g sinθ - sgn(v)(c_r M g cosθ + F_brake) - c_d v|v|, with sinθ = rise / hypot(travel, rise). The speed is capped by a governor (0.72 m/s) and explicit stepping uses dt = 25 ms.
Simplifications: massless inextensible rope, constant rolling coefficient, a quadratic drag law fitted by hand, no rope stretch, no drum inertia, no water-level dynamics in the caissons. Numbers are illustrative, not real canal data. The drawing exaggerates the vertical scale (about 3x) so the slope is visible.
Try: Heavy vessel (the loaded carriage descends and the drive must hold it), then Braking test.
Made with ChatGPT · 2D companion of the 3D page; same solver and numbers.